regulator: onsemi-ncp6335d: Fix compilation issues

Fix the compilation issue seen due to the regulator framework
changes from 3.10 to 4.4 kernel. Also remove the redundant error
messages during the memory allocation failures.

Change-Id: I4887c2d3acaff562fb41e6c2eaeb2c1ef2c1bde5
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>